Genomic insights of Leclercia adecarboxylata strains linked to an outbreak in public hospitals in Mexico.

BACKGROUND: Leclercia adecarboxylata is a bacteria closely related to Escherichia coli according to its biochemical characteristics and is commonly considered non-pathogenic although a growing number of publications classify it as an emerging pathogen. Fosfomycin resistance is a common trait for L. adecarboxylata encoded by fosALA gene. OBJECTIVE: To analyze genomic traits of sixteen L. adecarboxylata strains isolated from blood culture and a bottle of total parenteral nutrition. METHODS: Twenty-eight L. adecarboxylata strains isolated from blood culture and a bottle of total parenteral nutrition were identified biochemically with a Vitek ® automated system. The strains were phenotyped by their growth on Eosin Methylene Blue agar or MacConkey agar plates. Additionally, Pulsed field gel electrophoresis (PFGE) was performed to establish the clonal relationship. The genomic DNA of sixteen strains was obtained using a Qubit ® dsDNA HS Assay Kit and sequenced on an Illumina ® MiSeq instrument. Draft genomes were assembled using PROKKA and Rast. Assemblies were submitted to Resfinder and PathogenFinder from the Center for Genomic Epidemiology in order to find resistance genes and pathogenic potential. IslandViewer4 was also used to find Pathogenicity and Phage Islands. For identification of the fosA gene, manual curation and Clustal analysis was performed. A novel FosA variant was identified. Finally, phylogenetic analysis was performed using VAMPhyRE software and Mega X. RESULTS: In this paper, we report the genomes of sixteen strains of Leclercia adecarboxylata causing an outbreak associated with parenteral nutrition in public hospitals in Mexico. The genomes were analyzed for genetic determinants of virulence and resistance. A high pathogenic potential (pathogenicity index 0.82) as well as multiple resistance genes including carbapenemics, colistin and efflux pumps were determined. Based on sequence analysis, a new variant of the fosALA gene was described. Finally, the outbreak was confirmed by establishing the clonal relationship among the sixteen genomes obtained. CONCLUSIONS: Commensal strains of L. adecarboxylata may acquire genetic determinants that provide mechanisms of host damage and go unnoticed in clinical diagnosis. L. adecarboxylata can evolve in a variety of ways including the acquisition of resistance and virulence genes representing a therapeutic challenge in patient care.

[Breast cancer, the risk attributable to type 2 diabetes]. / Cáncer de mama, el riesgo atribuible a diabetes tipo 2.

BACKGROUND: Several studies have evaluated the association between a history of type 2 diabetes (T2D) and risk of breast cancer (BC), with controversial results. However, information regarding the population-attributable risk percent (PAR%) remains scarce. Objective: To estimate the association and the PAR% for BC and T2D, lifestyle and gynecologic factors in women in Mexico City. METHODS: This case-control study was performed from May-December 2020. Women >40 years of age, from Mexico City, with a confirmed diagnosis for BC were included as cases. Controls were women with a BIRADS 1 or 2 mammography or an ultrasound clear of any BC suggestive findings. RESULTS: A total of 134 cases and 134 controls were included. A higher risk for BC was identified among women who did not perform routine physical activity and those who had a history of hormonal contraceptive use > 5 years. The use of hormone replacement therapy (HRT) was associated with an odds ratio (OR) of 5.0 (p = 0.22) in the first model. After adjustment, HRT was associated with an OR of 2.92 (p=0.492) in the second and an OR of 3.6 (p = 0.753) in the third model. T2D was associated with an OR of 1.04 (p = 0.96) in the first model; an OR of 0.65 (p = 0.65) in the second model and an OR of RMa 0.75(p = 0.79) for the third model. CONCLUSION: In this case-control study, there was no significant association identified between a T2D diagnosis and BC.

INTRODUCCIÓN: diversas investigaciones han evaluado el riesgo de cáncer de mama (CaMa) asociado a diabetes tipo 2 (DT2) con resultados inconsistentes. Pocas investigaciones han evaluado el porcentaje de riesgo atribuible a la población (PAR%). OBJETIVO: estimar la asociación y el PAR% para CaMa por DT2, así como los factores del estilo de vida y ginecológicos en mujeres de la Ciudad de México. MÉTODOS: estudio de casos y controles, realizado de mayo a diciembre de 2020. Se incluyeron mujeres > 40 años, de la Ciudad de México, con diagnóstico confirmado de CaMa. Los controles fueron mujeres con una mastografía BIRADS 1 o 2, o ultrasonido mamario sin datos sugestivos de CaMa. RESULTADOS: se incluyeron en total 134 casos y 134 controles. Se identificó un mayor riesgo de CaMa en aquellas mujeres que no realizan actividad física y con el uso de anticonceptivos > 5 años. El uso de terapia de reemplazo hormonal (TRH) se asoció con una razón de momios ajustada (RMa) de 5.0, p = 0.22 en el modelo 1. Conforme se ajustan los modelos, la TRH para el modelo 2 tuvo una RMa de 2.92, p = 0.492 y en el modelo 3 una RMa de 3.6 p = 0.753. La presencia de diabetes se asoció a una RMa de 1.04, p = 0.96 en el modelo 1; RMa de 0.65, p = 0.65 en el modelo 2 y una RMa de 0.75, p = 0.79 en el modelo 3. CONCLUSIONES: en este estudio de casos y controles no se encontró asociación entre el diagnóstico de DT2 y CaMa.

Access to paediatric cancer care treatment in Mexico: responding to health system challenges and opportunities.

In Mexico, paediatric cancer is the leading cause of death for children aged 0-18 years. This study analyses the main challenges for paediatric cancer care from the perspective of three key health systems functions: stewardship, financing and service delivery. The study used a mixed methods approach comprised of: (1) a scoping literature review, (2) an analysis of 2008-18 expenditures on paediatric cancer by the Fund for Protection against Catastrophic Expenditures (FPGC) of Seguro Popular and (3) a nation-wide survey of the supply capacity of 59 Ministry of Health (MoH) and 39 Mexican Institute of Social Security (IMSS) hospitals engaged in paediatric cancer care. The study found that while Mexico has made substantial progress towards universal health coverage (UHC) for paediatric cancer treatment, serious gaps persist. FPGC funds for paediatric cancer increased from 2008 to 2011 to reach US$36 million and then declined to US$13.6 million in 2018, along with the number of covered cases. The distribution of health professionals and paediatric oncology infrastructure is uneven between MoH and IMSS hospitals and across Mexican regions. Both institutions share common barriers for continuous and co-ordinated health care and lack monitoring activities that cripple their capacity to apply uniform standards for high-quality cancer care. In conclusion, achieving universal and effective coverage of paediatric cancer treatment is a critical component of UHC for Mexico. This requires periodic and ongoing assessment of health system performance specific to paediatric cancer to identify gaps and propose strategies for continued investment and improvement of access to care and health outcomes for this important cause of premature mortality.

Incidence, mortality and associated costs of lung cancer in the Mexican Institute of Social Security.

OBJECTIVE: To describe temporal trends in lung cancer incidence, mortality and associated health care costs in the Mexican Institute of Social Security. MATERIALS AND METHODS: . Incident cases were estimated from hospital discharges in 276 IMSS hospitals between 2006 and 2016. Crude and adjusted mortality rates were calculated. The costs of outpatient and inpatient treatment were calculated based on the medical-technical costs of reference o standard cost. RESULTS: Both incidence and mortality had a decreased time trend. The cost of medical care for the 2 539 patients in 2017 was 42 million US dollars, with an average cost per patient of 16 537 US dollars. The cost per annum of disability pensions is 97.2 million pesos. CONCLUSIONS: It is likely that the reduction of the risk of getting sick and dying from lung cancer in IMSS affiliates is due to the control measures of tobacco smoke. It is still necessary to establish strategies to diagnose and treat patients in early stages.

OBJETIVO: Analizar la tendencia temporal de la incidencia y la mortalidad del cáncer de pulmón, así como los costos asociados con su atención médica. MATERIAL Y MÉTODOS: Se estimó el número de casos incidentes a partir de los egresos hospitalarios de 276 hospitales del Instituto Mexicano del Seguro Social (IMSS) entre 2006 y 2016. Se calcularon tasas de mortalidad crudas y ajustadas. Los costos del tratamiento ambulatorio y hospitalario se calcularon con base en los costos médico-técnicos de referencia o costos estándar de 2015. RESULTADOS: Tanto la incidencia como la mortalidad muestran tendencia descendente. El costo de la atención médica de los 2 539 pacientes de 2017 fue de 42 millones de dólares americanos, con costo promedio por paciente de 16 527 dólares americanos. El gasto promedio anual de pensiones por invalidez es de 97.2 millones de pesos. CONCLUSIONES: probable que la reducción del riesgo de enfermar y mo- rir por cáncer de pulmón en derechohabientes del IMSS se deba a las medidas de control del humo de tabaco. Todavía es necesario establecer estrategias para diagnosticar y tratar a los pacientes en estadios tempranos.

Incidencia, mortalidad y costos de la atención por cáncer de pulmón en el Instituto Mexicano del Seguro Social / Incidence, mortality and associated costs of lung cancer in the Mexican Institute of Social Security

Resumen: Objetivo: Analizar la tendencia temporal de la incidencia y la mortalidad del cáncer de pulmón, así como los costos asociados con su atención médica. Material y métodos: Se estimó el número de casos incidentes a partir de los egresos hospitalarios de 276 hospitales del Instituto Mexicano del Seguro Social (IMSS) entre 2006 y 2016. Se calcularon tasas de mortalidad crudas y ajustadas. Los costos del tratamiento ambulatorio y hospitalario se calcularon con base en los costos médico-técnicos de referencia o costos estándar de 2015. Resultados: Tanto la incidencia como la mortalidad muestran tendencia descendente. El costo de la atención médica de los 2 539 pacientes de 2017 fue de 42 millones de dólares americanos, con costo promedio por paciente de 16 527 dólares americanos. El gasto promedio anual de pensiones por invalidez es de 97.2 millones de pesos. Conclusiones: Es probable que la reducción del riesgo de enfermar y morir por cáncer de pulmón en derechohabientes del IMSS se deba a las medidas de control del humo de tabaco. Todavía es necesario establecer estrategias para diagnosticar y tratar a los pacientes en estadios tempranos.

Abstract: Objective: To describe temporal trends in lung cancer incidence, mortality and associated health care costs in the Mexican Institute of Social Security. Materials and methods: Incident cases were estimated from hospital discharges in 276 IMSS hospitals between 2006 and 2016. Crude and adjusted mortality rates were calculated. The costs of outpatient and inpatient treatment were calculated based on the medical-technical costs of reference o standard cost. Results: Both incidence and mortality had a decreased time trend. The cost of medical care for the 2 539 patients in 2017 was 42 million US dollars, with an average cost per patient of 16 537 US dollars. The cost per annum of disability pensions is 97.2 million pesos. Conclusions: It is likely that the reduction of the risk of getting sick and dying from lung cancer in IMSS affiliates is due to the control measures of tobacco smoke. It is still necessary to establish strategies to diagnose and treat patients in early stages.

The burden of disease of cancer in the Mexican Social Security Institute.

OBJECTIVE: To estimate the disease burden of cancer in the affiliate population of the Mexican Social Security Institute (Instituto Mexicano del Seguro Social, IMSS) in 2010 by delegation. MATERIALS AND METHODS: The Disability-Adjusted Life Years (DALYs), Years of Life Lost (YLL) due to premature mortality and Years Lived with Disability/Disease (YLD) for 21 specific cancers and a subgroup of other malignant neoplasms were calculated based on the methodology of the Global Burden of Disease Study (GBD) for each of the 35 delegations of the IMSS. RESULTS: In 2010, cancer represented the fifth overall leading cause of disease burden in IMSS affiliates (16.72 DALYs/1000 affiliates). A total of 75% of the cancer disease burden in each delegation is due to ten specific cancers, particularly breast cancer, which ranks first in 82% of the delegations. Prostate cancer; tracheal, bronchial, and lung cancers; leukemia, and colorectal and stomach cancers occupy the second to fourth positions in each delegation. With the exception of breast and prostate cancer, for which the contribution of YLD to the DALYs was higher than 50%, the greatest contribution to the DALYs of the other cancers was premature mortality, which accounted for more than 90% of the DALYs in some cases. CONCLUSION: The results obtained in this study allow for the identification of intervention priorities with regard to cancer at the institutional level and also for the focus at the delegation level to be placed on cancers ranking in the top positions for disease burden.

Cancer mortality in the Mexican Social Security Institute, 1989-2013.

UNLABELLED: Objetive: To analyze cancer mortality in affiliates of the Mexican Social Security Institute (Instituto Mexicano del Seguro Social - IMSS) and time trends in the risk of death due to cancer from 1989 to 2013. MATERIALS AND METHODS: A descriptive analysis of cancer mortality trends in beneficiaries of the IMSS was performed. Age- and sex-adjusted mortality rates were obtained using direct standardization with the WHO population. Changes in the risk of death due to cancer over time were evaluated using Poisson regression. RESULTS: The absolute number of deaths due to cancer doubled from 1989 to 2013 due to increasing age of the affiliate population. The risk of death among affiliates decreased for the majority of cancers except for colon and rectal cancer. CONCLUSION: The risk of dying from cancer among IMSS affiliates showed a marked decrease, which may be due to an increase in detection and opportune treatment.

Cancer mortality in the Mexican Social Security Institute, 1989-2013 / Mortalidad por cáncer en el Instituto Mexicano del Seguro Social, 1989-2013

Abstract Objetive: To analyze cancer mortality in affiliates of the Mexican Social Security Institute (Instituto Mexicano del Seguro Social - IMSS) and time trends in the risk of death due to cancer from 1989 to 2013. Materials and Methods: A descriptive analysis of cancer mortality trends in beneficiaries of the IMSS was performed. Age- and sex-adjusted mortality rates were obtained using direct standardization with the WHO population. Changes in the risk of death due to cancer over time were evaluated using Poisson regression. Results: The absolute number of deaths due to cancer doubled from 1989 to 2013 due to increasing age of the affiliate population. The risk of death among affiliates decreased for the majority of cancers except for colon and rectal cancer. Conclusion: The risk of dying from cancer among IMSS affiliates showed a marked decrease, which may be due to an increase in detection and opportune treatment.

Resumen Objetivo: Analizar la frecuencia de las defunciones por cáncer en la población derechohabiente (DH) del Instituto Mexicano del Seguro Social, así como la tendencia temporal en el riesgo de muerte por esta causa de 1989 a 2013. Material y métodos: Se realizó análisis descriptivo del comportamiento de la mortalidad por cáncer en población derechohabiente del IMSS. Las tasas de mortalidad ajustadas por edad y sexo se obtuvieron con el método directo utilizando la población mundial estándar de la OMS. Los cambios en el riesgo de morir por cáncer a través del tiempo se evaluaron mediante regresión de Poisson. Resultados: El número absoluto de defunciones por cáncer se duplicó de1989 a 2013 debido a un aumento y al envejecimiento de la población derechohabiente. El riesgo de muerte en los DH disminuyó para la mayoría de los diferentes tipos de cáncer, excepto para el cáncer de colon y recto. Conclusión: El riesgo de morir por cáncer en DH del IMSS muestra una discreta disminución, posiblemente debido a la mejora en la detección y tratamiento oportuno.

The burden of disease of cancer in the Mexican Social Security Institute / La carga de la enfermedad debida al cáncer en el Instituto Mexicano del Seguro Social

Abstract: Objective: To estimate the disease burden of cancer in the affiliate population of the Mexican Social Security Institute (Instituto Mexicano del Seguro Social, IMSS) in 2010 by delegation. Materials and methods: The Disability-Adjusted Life Years (DALYs), Years of Life Lost (YLL) due to premature mortality and Years Lived with Disability/Disease (YLD) for 21 specific cancers and a subgroup of other malignant neoplasms were calculated based on the methodology of the Global Burden of Disease Study (GBD) for each of the 35 delegations of the IMSS. Results: In 2010, cancer represented the fifth overall leading cause of disease burden in IMSS affiliates (16.72 DALYs/1000 affiliates). A total of 75% of the cancer disease burden in each delegation is due to ten specific cancers, particularly breast cancer, which ranks first in 82% of the delegations. Prostate cancer; tracheal, bronchial, and lung cancers; leukemia, and colorectal and stomach cancers occupy the second to fourth positions in each delegation. With the exception of breast and prostate cancer, for which the contribution of YLD to the DALYs was higher than 50%, the greatest contribution to the DALYs of the other cancers was premature mortality, which accounted for more than 90% of the DALYs in some cases. Conclusion: The results obtained in this study allow for the identification of intervention priorities with regard to cancer at the institutional level and also for the focus at the delegation level to be placed on cancers ranking in the top positions for disease burden.

Resumen: Objetivo: Estimar, por delegación, la carga de enfermedad debida al cáncer en la población derechohabiente del Instituto Mexicano del Seguro Social (IMSS) para el año 2010. Material y métodos: Se calcularon los años de vida perdidos ajustados por discapacidad (AVISA), los años perdidos por muerte prematura (APMP) y los años vividos con discapacidad (AVD) para 21 cánceres específicos y un subgrupo de otras neoplasias malignas, con base en la metodología del Global Burden of Disease Study (GBD) para cada una de las 35 delegaciones en las que se divide el IMSS al interior del país. Resultados: En el año 2010, el cáncer representó la quinta causa de carga de enfermedad en derechohabientes del IMSS (16.72 AVISA/1000 derechohabientes). El 75% de la carga de enfermedad por cáncer en cada delegación se debe a diez cánceres específicos entre los que destaca el cáncer de mama, que ocupa el primer lugar de importancia en 82% de las delegaciones. Los cánceres de próstata, tráquea, bronquios y pulmón, leucemias, de colon y recto, así como el de estómago, se ubican entre las segundas y cuartas posiciones en cada delegación. Con excepción del cáncer de mama y de próstata, cuya contribución de los AVD a los AVISA fue superior a 50%, en los demás cánceres la mayor contribución fue debida a la mortalidad prematura, en algunos superior a 90% de los AVISA. Conclusión: Los resultados obtenidos en este estudio permiten identificar las prioridades de intervención en materia de cáncer a nivel institucional y focalizarlas a nivel delegacional para los cánceres que ocupan los primeros lugares de carga de enfermedad.

Evaluation of the impact on non-communicable chronic diseases of a major integrated primary health care program in Mexico.

BACKGROUND: Primary health care is the best framework for implementing actions for the prevention and control of non-communicable diseases at an appropriate scale. In 2002, the Mexican Institute for Social Security (IMSS), which provides health care to half of the Mexican population, implemented a primary care-based integrated program that included the improvement of the family health care practice and a preventive strategy called PREVENIMSS, to reduce the burden of disease. OBJECTIVE: To asess the impact of this program on selected non-communicable chronic diseases. METHODS: Morbidity and mortality were compared before and after implementation of the program and time trends in IMSS affiliates and non-affiliates using the difference-in-differences (DD) method. RESULTS: Incidence rates of diabetes and hypertension increased whereas those of cervical cancer, breast cancer and other cerebrovascular diseases decreased from 2000 to 2013. The DD in mortality rates, expressed per 100000 persons, showed a decrease of 49.4 for diabetes mellitus, 9.1 for hypertensive disease, 42.9 for ischemic heart disease, 17.4 for cerebrovascular disease, 7.5 for cervical cancer and 5.8 for breast cancer. CONCLUSIONS: The reductions in mortality rates could be explained by both changes in incidence rates and changes in case fatality rates associated with early detection and treatment. These initial findings can be interpreted as the potential impact of integrated programs based on primary health care in a developing country.

Impact of antiviral treatment and hospital admission delay on risk of death associated with 2009 A/H1N1 pandemic influenza in Mexico.

BACKGROUND: Increasing our understanding of the factors affecting the severity of the 2009 A/H1N1 influenza pandemic in different regions of the world could lead to improved clinical practice and mitigation strategies for future influenza pandemics. Even though a number of studies have shed light into the risk factors associated with severe outcomes of 2009 A/H1N1 influenza infections in different populations, analyses of the determinants of mortality risk spanning multiple pandemic waves and geographic regions are scarce. Between-country differences in the mortality burden of the 2009 pandemic could be linked to differences in influenza case management, underlying population health, or intrinsic differences in disease transmission. Additional studies elucidating the determinants of disease severity globally are warranted to guide prevention efforts in future influenza pandemics.In Mexico, the 2009 A/H1N1 influenza pandemic was characterized by a three-wave pattern occurring in the spring, summer, and fall of 2009 with substantial geographical heterogeneity. A recent study suggests that Mexico experienced high excess mortality burden during the 2009 A/H1N1 influenza pandemic relative to other countries. However, an assessment of potential factors that contributed to the relatively high pandemic death toll in Mexico are lacking. Here, we fill this gap by analyzing a large series of laboratory-confirmed A/H1N1 influenza cases, hospitalizations, and deaths monitored by the Mexican Social Security medical system during April 1 through December 31, 2009 in Mexico. In particular, we quantify the association between disease severity, hospital admission delays, and neuraminidase inhibitor use by demographic characteristics, pandemic wave, and geographic regions of Mexico. METHODS: We analyzed a large series of laboratory-confirmed pandemic A/H1N1 influenza cases from a prospective surveillance system maintained by the Mexican Social Security system, April-December 2009. We considered a spectrum of disease severity encompassing outpatient visits, hospitalizations, and deaths, and recorded demographic and geographic information on individual patients. We assessed the impact of neuraminidase inhibitor treatment and hospital admission delay (≤ > 2 days after disease onset) on the risk of death by multivariate logistic regression. RESULTS: Approximately 50% of all A/H1N1-positive patients received antiviral medication during the Spring and Summer 2009 pandemic waves in Mexico while only 9% of A/H1N1 cases received antiviral medications during the fall wave (P < 0.0001). After adjustment for age, gender, and geography, antiviral treatment significantly reduced the risk of death (OR = 0.52 (95% CI: 0.30, 0.90)) while longer hospital admission delays increased the risk of death by 2.8-fold (95% CI: 2.25, 3.41). CONCLUSIONS: Our findings underscore the potential impact of decreasing admission delays and increasing antiviral use to mitigate the mortality burden of future influenza pandemics.

Recrudescent wave of pandemic A/H1N1 influenza in Mexico, winter 2011-2012: Age shift and severity.

BACKGROUND: A substantial recrudescent wave of pandemic influenza A/H1N1 that began in December 2011 is ongoing and has not yet peaked in Mexico, following a 2-year period of sporadic transmission. Mexico previously experienced three pandemic waves of A/H1N1 in 2009, associated with higher excess mortality rates than those reported in other countries, and prompting a large influenza vaccination campaign. Here we describe changes in the epidemiological patterns of the ongoing 4th pandemic wave in 2011-12, relative to the earlier waves in 2009. The analysis is intended to guide public health intervention strategies in near real time. METHODS: We analyzed demographic and geographic data on all hospitalizations with acute respiratory infection (ARI) and laboratory-confirmed A/H1N1 influenza, and inpatient deaths, from a large prospective surveillance system maintained by the Mexican Social Security medical system during 01-April 2009 to 10-Feb 2012. We characterized the age and regional patterns of A/H1N1-positive hospitalizations and inpatient-deaths relative to the 2009 A/H1N1 influenza pandemic. We also estimated the reproduction number (R) based on the growth rate of the daily case incidence by date of symptoms onset. RESULTS: A total of 5,795 ARI hospitalizations and 186 inpatient-deaths (3.2%) were reported between 01-December 2011 and 10-February 2012 (685 A/H1N1-positive inpatients and 75 A/H1N1-positive deaths). The nationwide peak of daily ARI hospitalizations in early 2012 has already exceeded the peak of ARI hospitalizations observed during the major fall pandemic wave in 2009. The mean age was 34.3 y (SD=21.3) among A/H1N1 inpatients and 43.5 y (SD=21) among A/H1N1 deaths in 2011-12. The proportion of laboratory-confirmed A/H1N1 hospitalizations and deaths was higher among seniors >=60 years of age (Chi-square test P<0.001) and lower among younger age groups (Chi-square test, P<0.03) for the 2011-2012 pandemic wave, compared to the earlier waves in 2009. The reproduction number of the winter 2011-12 wave in central Mexico was estimated at 1.2-1.3, similar to that reported for the fall 2009 wave, but lower than that of spring 2009. CONCLUSIONS: We have documented a substantial and ongoing increase in the number of ARI hospitalizations during the period December 2011-February 2012 and an older age distribution of laboratory-confirmed A/H1N1 influenza hospitalizations and deaths, relative to 2009 A/H1N1 pandemic patterns. The gradual change in the age distribution of A/H1N1 infections in the post-pandemic period is reminiscent of historical pandemics and indicates either a gradual drift in the A/H1N1 virus, and/or a build-up of immunity among younger populations.

[Estimating the incidence of 2009 pandemic influenza A(H1N1) among IMSS affiliates]. / Estimación de la incidencia de influenza pandémica A(H1N1) 2009 en derechohabientes del Instituto Mexicano del Seguro Social.

INTRODUCTION: The purpose of this study is to estimate the burden of the disease associated to pandemic 2009 influenza virus, from April 2009 to January 2010. METHODS: To estimate the number of symptomatic cases, the number of hospitalizations and deaths we used the Center for Disease Control (CDC) recommended method that takes into account the underestimation associated with the use of health services, the practices of confirmation and registration of cases.To estimate the incidence of infection, we applied the recently reported London sero-incidence by age group to the IMSS population. RESULTS: Each case of symptomatic confirmed influenza represented 51 cases during the first wave and 18 in the second wave. We estimate 537,167 (range 378,439-813,008) symptomatic cases. Each confirmed hospitalized person represented 2.2 cases. The estimate of hospitalizations was 10,063 (range 7,441-14,610). The ratio of hospitalization to the total number of cases was 1.8%. The estimated incidence of infection was close to 24%. CONCLUSIONS: Confirmed cases in the epidemiological surveillance system are only a small proportion of the population infected and symptomatic cases, information relevant in planning new outbreaks.

Infection and death from influenza A H1N1 virus in Mexico: a retrospective analysis.

BACKGROUND: In April, 2009, the first cases of influenza A H1N1 were registered in Mexico and associated with an unexpected number of deaths. We report the timing and spread of H1N1 in cases, and explore protective and risk factors for infection, severe disease, and death. METHODS: We analysed information gathered by the influenza surveillance system from April 28 to July 31, 2009, for patients with influenza-like illness who attended clinics that were part of the Mexican Institute for Social Security network. We calculated odds ratios (ORs) to compare risks of testing positive for H1N1 in those with influenza-like illness at clinic visits, the risk of admission for laboratory-confirmed cases of H1N1, and of death for inpatients according to demographic characteristics, clinical symptoms, seasonal influenza vaccine status, and elapsed time from symptom onset to admission. FINDINGS: By July 31, 63 479 cases of influenza-like illness were reported; 6945 (11%) cases of H1N1 were confirmed, 6407 (92%) were outpatients, 475 (7%) were admitted and survived, and 63 (<1%) died. Those aged 10-39 years were most affected (3922 [56%]). Mortality rates showed a J-shaped curve, with greatest risk in those aged 70 years and older (10.3%). Risk of infection was lowered in those who had been vaccinated for seasonal influenza (OR 0.65 [95% CI 0.55-0.77]). Delayed admission (1.19 [1.11-1.28] per day) and presence of chronic diseases (6.1 [2.37-15.99]) were associated with increased risk of dying. INTERPRETATION: Risk communication and hospital preparedness are key factors to reduce mortality from H1N1 infection. Protective effects of seasonal influenza vaccination for the virus need to be investigated. FUNDING: None.